Study: Keep Systolic BP in Therapeutic Range

LOS ANGELES—Physicians should aim for long-term maintenance of systolic blood pressure (BP) in the therapeutic range in their hypertensive patients, investigators said here at the American Heart Association Scientific Sessions 2012.

Vasilios Papademetriou, MD, Professor of Medicine at Georgetown University in Washington D.C., and colleagues examined the relationship between time in the therapeutic range and all-cause mortality over a recent 10-year period in 371,996 hypertensive patients who were treated at Veterans Administration medical centers.

Their results showed that long-term maintenance of systolic BP in the therapeutic range of 120- 140 mm Hg was associated with a lower risk of death than maintaining systolic BP above or below that range.

“I believe that the 120-140 mm Hg [systolic] blood pressure range is the most appropriate for our patients, particularly those at high risk because of coronary disease or diabetes or other co-morbidities,” said Dr. Papademetriou, Director of Hypertension and Cardiovascular Research at the Veterans Affairs Medical Center in Washington D.C.

High BP has long been known to dramatically increase the risk of cardiovascular events and all-cause mortality, but multiple prospective studies and cohort analyses have suggested that lowering systolic BP to below 140 mm Hg improves health outcomes, he said. The optimal systolic BP level, however, had not been identified.

The analysis revealed that patients whose systolic BP was in the therapeutic range for 75% or more of the times their blood pressure was measured had a mortality rate of 6.54%. The mortality rates were 21.9% and 33%, respectively, among patients whose systolic BP was above or below the therapeutic range 75% or more of the time.

Although the mortality risk was lowest in patients who maintained their systolic BP in the therapeutic range more than 75% of the time, the risk only increased slightly if the pressure was maintained in the therapeutic range 51%-75% if the time. If it remained in the therapeutic range 25% or less of the time, the mortality rate surged to 23.5%.

“So it seems like we found from our retrospective, observational data in a large number of patients that a window of 120-40 mm Hg provides the best survival benefit in hypertensive patients,” Dr. Papademetriou told Renal & Urology News. “If you are above or below this level most of the time, the mortality rate is much higher.”

He also said he is not yet certain whether the findings will eventually prompt a change in current guidelines, which recommend a goal systolic BP below 140 mm Hg. “The common notion has been ‘the lower, the better.' The thinking has been that if you could reduce it to 130 mm Hg, that was fine. But if you could decrease it to 110 mm Hg, that was even better. We now know that that's not the case.”

He emphasized that the data “obviously need to be validated in a prospective studies."

Dr. Papademetriou pointed out that his team obtained information about blood pressure measurements from electronic medical records. Notably, patients had their blood pressure measured, on average, 44 times throughout the entire study period. “In most studies, blood pressure is measured much less frequently,” he said.